How Photovoltaics Work
Solar power is credited to be one of the most important breakthroughs of the last century. Harnessing the power of the sun is seen by many scientists and energy experts as the solution to our dependency on fossil fuels, which are not only contributing to environmental pollution, but can also be depleted over time. Photovoltaics has been used in different parts of the world as a means to supplement electricity demands, and energy experts are optimistic that the growth of the solar power industry means that we could expect a higher annual generation of electricity through this process.
The word “photovoltaic” was derived from the Greek word “phos” (light) and “volt,” which was derived from Alessandro Volta, the Italian physicist who invented the electrochemical cell. Photovoltaic cells, also known as solar cells, is basically a type of electric device that has the ability to convert light energy into electricity through the photovoltaic effect.
The photovoltaic effect is also known as the Becquerel effect, named after the French physicist Edmond Becquerel who discovered it in 1839. At the tender age of 19, Becquerel experimented with silver chloride (in an acidic solution) and platinum electrodes. When connected and exposed to light, the chemical and the electrodes generated electric currents and voltage. This “little” experiment won Becquerel a seat in the Royal Swedish Academy of Sciences.
Photovoltaic cells are the core of the technology. There are three basic attributes to a photovoltaic cell. First, it has the capacity to absorb light and to generate excitons or electron-hole pairs. Second, it has the capacity to separate charge carriers with opposite types. Finally, it has the capacity the separate the extraction of charge carriers to an external circuit connected to it.
Photovoltaic cells are made with semiconductor materials, with silicon as the most used material in the industry. The solar cells are semiconductor wafers, which are treated with chemicals that allow the formation of electric field. When exposed to light, the electrons on the semiconductor material will be loosened from the atoms they are attached to. The electrical conductors connected to the positive and negative sides of the solar cell will then form an electrical circuit, and the loosened electrons will then be captured as an electrical current.
When connected to each other and mounted on a frame, solar cells will form a photovoltaic module. These modules are often designed to generate and supply electricity at a specified voltage, with 12 volts being one of the most common kinds of solar modules. Since these modules depend on solar power, the amount of electricity that they can generate is dependent on the amount of light that they absorb.
When wired together, multiple modules form an array. The larger the array (or, the more modules grouped together), the higher amount of electricity it can produce. Solar arrays generate direct-current (or DC) electricity, and can be connected in either a parallel or series electrical arrangement to deliver the current and voltage combination needed.